Issue SSE stream ticket

Exchange the API key for a short-lived (~60s), single-use ticket, then open the live message stream at GET .../messages/stream?ticket=<ticket>. Required because EventSource cannot send Authorization headers. The ticket is bound to this agent + conversation and consumed on first use. Requires the conversations:read scope.

curl -X POST "https://example.com/api/v1/console/agents/string/conversations/string/stream-ticket"

{  "message": "Stream ticket issued",  "data": {    "ticket": "b6pLGUmOFBXhD5TkxxlXRxOyzbRO3I0FICszBwFmdrg",    "expires_in": 60  }}

{  "message": "Resource not found",  "error": "Not Found",  "code": "not_found",  "statusCode": 404,  "request_id": "266ea41d-adf5-480b-af50-15b940c2b846"}